Protein Prince vs. Protein Pauper: Which Will it be Tonight?

Johns Hopkins researchers have made a discovery that may help explain why humans have so few genes to create such high complexity. It looks as if some common blue-collar proteins may be moonlighting as princely transcription factors -- controlling gene expression. One day a prince, another a pauper. Whatever is a protein to do?

Now, a collaborative effort at the Johns Hopkins School of Medicine to examine protein-DNA interactions across the whole genome has uncovered more than 300 proteins that appear to control genes, a newly discovered function for all of these proteins previously known to play other roles in cells. The results, which appear in the October 30 issue of Cell, provide a partial explanation for human complexity over yeast but also throw a curve ball in what we previously understood about protein functions.


...The team suspects that many more proteins encoded by the human genome might also be moonlighting to control genes, which brings researchers to the paradox that less complex organisms, such as plants, appear to have more transcription factors than humans. "Maybe most of our genes are doing double, triple or quadruple the work," says Zhu. "This may be a widespread phenomenon in humans and the key to how we can be so complex without significantly more genes than organisms like plants."


...One of the unconventional transcription factors discovered was the protein MAP Kinase 1, also known as ERK2, a protein long studied for its ability to control cell growth and development via its ability to add phosphate groups to other molecules.


"It's one of the best studied proteins out there, but no one ever thought ERK2 could directly regulate gene expression by actually binding to DNA," says Seth Blackshaw, Ph.D., an assistant professor of neuroscience and a member of the High Throughput Biology Center and the Neuroregeneration Program at the Institute for Cell Engineering. _SD

It is said that testosterone levels for human geneticists fell significantly when they learned that many plants and lower animals possessed higher numbers of genes than the human genome. Perhaps understanding how a more complex gene expression mechanism can make up for a smaller number of genes, will restore these geneticists to their former prowess.